1. Field of the Invention
The present invention relates to a drive circuit for a semiconductor device.
2. Background Art
Conventionally, as disclosed, for example, in Japanese Patent Laid-Open No. 2011-259529, a drive circuit for a semiconductor device is known which receives a supply of control power from a converter power supply circuit. The device according to this publication is more specifically an inverter circuit provided with a so-called arm circuit which is a set of semiconductor switching devices connected in series and a drive circuit that gives a drive signal to each semiconductor switching device of this arm circuit. This inverter circuit allows a load of a motor or the like to be driven.
Other prior art includes Japanese Laid-Open Patent Publication No. 2004-47937 and Japanese Laid-Open Patent Publication No. 2011-259531.
When a certain abnormality is detected in an inverter system including the above-described inverter circuit, the drive circuit generally stops outputting a drive signal thereof and stops driving the semiconductor switching device. This makes it possible to stop operation of the inverter system in the event of an abnormality and secure safety.
In the above prior art, control power is supplied from the converter power supply circuit to the drive circuit. This control power is generated through switching of another semiconductor switching device included in the converter power supply circuit. Conventionally, this converter drive circuit operates independently of the drive circuit.
In this case, even when the drive circuit stops output due to an abnormality in the inverter system, the converter drive circuit tries to continue to generate and supply the control power independently. As a result, this ends up being a waste of control power still being supplied to the drive circuit even in the event of an abnormality when the drive circuit stops output, unchanged from normal operation, and there is still room for improvement from the standpoint of reducing power consumption.